public class test54 {
    public static void main(String[] args) {
        int[] arr = {1,2,3};
        String str = newString(arr);
        System.out.println(str);
    }
    public static String newString(int[] arr) {
        StringBuilder sb = new StringBuilder("[");
        for (int i = 0; i < arr.length; i++) {
            if(i==arr.length-1){
                sb.append(arr[i]+"]");}
        else         {
                    sb.append(arr[i]+",");
                }

            }
      String s = sb.toString();
        return s;
    }
}
